The leaflet sought to caution voters against supporting the Labour Party, claiming that Havering was “in danger”, next to photos of Labour leader Jeremy Corbyn and London mayor Sadiq Khan.

A Conservative leaflet for the May 3 local election in the London borough of Havering has revived memories of Enoch Powell’s infamous 1968 “rivers of blood” speech, sparking criticism from inside and outside the party, and forcing an apology and withdrawal.

The forthcoming elections in London boroughs, councils, unitary authorities and mayoralties in England again reflect the primacy of the sensitive issue of race and immigration in elections in Britain. Powell’s speech was made in the context of concerns at the time about immigration from India and the Commonwealth.

The leaflet issued by the local Conservative councillors sought to caution voters against supporting the Labour Party, claiming that Havering was “in danger”, next to photos of Labour leader Jeremy Corbyn and London mayor Sadiq Khan.

It suggests that if Labour were elected in the council, not only would taxes rise but people should get ready for “Havering resembling boroughs like Hackney, Newham, Camden and Barking, rather than a traditional part of Essex”.

Binita Mehta-Parmar, a Conservative candidate in Watford and a director of centre-right campaign Modern Britain, said Powell’s legacy was reflected in the leaflet: “It deeply saddens me to say that his legacy lives on almost 50 years later.”

“In recent elections, we have made progress in beginning to shift public perceptions among ethnic minority voters. As a young Asian woman from a Labour background, I am acutely aware of this,” she said, referring to the growing Indian and other minority votes for the party.

“Convincing those who assume the Tories are not for them is key to us regaining a majority government when the time comes. However, this Havering leaflet conveys exactly the wrong message and will be used by our political opponents to demonstrate that we are willing to use race to win votes,” she added.

The leaflet drew criticism from various quarters, including Labour MPs who saw it as a “case study of racist signalling”. Labour MP David Lammy said: “You don’t have to be a genius to realise this leaflet is one long dog whistle about race and the diversity that the vast majority of Londoners are so proud of.”

A Conservative spokesperson said: “Romford Conservatives intended to highlight local concerns about housing pressures, high-density urbanisation and badly-run Labour councils in inner London. They have apologised for any offence caused and the leaflet has been withdrawn.”

As the first major election since the 2017 mid-term election in which Prime Minister Theresa May lost majority, the May 3 local elections will be another test for her as well as Labour’s claims of gaining more support in the context of tensions over Brexit.